An unmanned flying device is an aircraft without an on-board human pilot. Unmanned flying devices are known and identified by different names or titles including Unmanned Aerial Vehicles (hereinafter UAVs), Remotely Piloted Aircraft Systems (RPAS), drones, Remotely Piloted Vehicles (RPVs) and the like. These UAVs may be classified and categorized in terms of range or altitude, shapes, sizes, roles and the like. In terms of different military roles, UAVs can be used in areas including electronic attack (EA), strike missions, suppression and/or destruction of enemy air defense (SEAD/DEAD), network node or communications relay, combat search and rescue (CSAR), and the like. In addition, there a multiple civilian purposes and roles for UAVs such as survey, inspection, search and rescue, security, and surveillance. Moreover, the UAV has different components to perform the above mentioned goals.
Typically, the UAV has components which include an airframe, a propulsion system, a flight control computer or system, a navigation system, a sensor system, actuators, wings, engines, lights, sensors, radio interfaces, optical sensors, audio sensors and the like. The complete system having one or more UAVs and a ground control station, data links, displays, controls, remote human operators and the like, can be referred to as the Unmanned Aerial System (hereinafter UAS). Moreover, the UAV can be controlled either autonomously, based on pre-programmed route and/or mission data, or by the remote operator present on the ground control station.
The ground control station controls and communicates with one or more UAVs using data links. Moreover, one or more UAVs communicate with each other through the data links. Further, the data links between one or more UAVs and the ground control station are based on wireless links, satellite links, radio links and the like.
Traditionally, UAVs were simply used as a remotely operated aircrafts, without having proper autonomous control over the flight of the unmanned flying device. However, with the advancement in technology, these UAVs utilize autonomous control to control the flight. Moreover, depending upon situations, these UAVs can operate in different modes including normal flying mode, safe landing mode, emergency landing mode and the like. The normal flying mode and the safe landing mode are normal and convenient; however, the problem lies in the emergency landing mode. The emergency landing mode corresponds to landing in error situations when one or more functionalities of the UAV partially or completely break down or interrupt. In such situations, landing becomes difficult and risky. Thus, proper control is needed to minimize the damage caused.
In an example, an error such as loss of sensor logic or non-functioning of radio communication to ground control station may occur. In such situations, the UAV may crash on the ground, hit an object in the air or land on some undesired location such as military UAV landing on the land of hostile forces. The uncontrolled landing may pose serious danger to other aircrafts, to birds and to the persons on the ground. The damage caused by uncontrolled landing can be extreme due to considerable weight of the UAV in tens, hundreds or thousands of kilograms. When such an UAV drops on a street with people and cars, accident or even death might occur. Moreover, when such an UAV collides with a passenger airplane in air, the impact may destroy the whole aircraft causing hundreds of human casualties. Further, the UAV itself may be damaged or destroyed due to uncontrolled landing, leading to financial loss.
Traditionally, parachutes control the landing of the UAV in fatal or erroneous situations. However, parachutes are not adequate as they may result in uncontrolled landing to an arbitrary place. The landing may occur in areas with people, driving cars or some nuclear facility. Moreover, the UAV may collide in air with other aircraft. In any of the stated situations, the impact may cause death, accident or even a major disaster. Further, the recovery of the UAV may be difficult or impossible due to the arbitrary location of the emergency landing, leading to a loss of equipment and/or loss of data and/or enabling hostile ground units to recover the UAV for reverse-engineering and analysis.
In view of the aforementioned problems discussed above, there is a need for a method for controlling the emergency landing with high precision to minimize or avoid disaster. Moreover, the method should appropriately select the mode of operation of the UAV based on predictable results of operating with such errors in the UAV.